Immerse yourself fully in the thought:
Impersonal higher self
Here it is not a matter of contemplating some idea predetermined by someone else, but of trying to form the best picture of the "higher self" that is possible at one's current stage of development.
Now place this picture, as it were, in the head's interior, roughly where the pineal gland is located. Transpose your awareness there for a while, and fill it entirely with the above thought: "impersonal higher self." Thus for a while imagine that your own being is contracted in the pineal gland, and that you are yourself the thought: "impersonal higher self." Banish all else from your awareness.
Having done this for a while, guide this thought slowly in a straight line from the pineal gland to the start of the spinal cord, at roughly the point where the brain passes into the spinal cord. Then lead it from there downward roughly in the region of the spinal cord to the point that is called K [kundalini]. Having imagined that one has there thoroughly infused the above thought with kundalini power, lead it slowly upward again, along the spinal cord, to a point in the interior of the head: roughly at the point (B) of the small cerebellum (occiput). Now guide this thought (impersonal higher self) in two lines from this point to both eyes, allowing it to stream out through these into infinite space. Then draw them back in again through the eyes and lead them to point B. Repeat this by leading the thought from B to both ears, allowing it stream out through them into infinite space and then leading it back through the ears to B again.
Having imagined that the thought "impersonal higher self" has twice been led through universal space and has been filled with its content, lead the thought, thus enriched, back from B through the spinal cord to K, imbue it in imagination with spiritual fire and then lead it very slowly to the throat (larynx level); so slowly that the time it takes to rise from K to this point will be about 20 minutes. Arriving there, think intensively:
I am not you.
I: the thought of the higher self after all the paths that it has taken in the meditation.
You: the ordinary I, with which one does not identify at this moment.
Source: Soul Exercises [CW 267], pp. 375-6; cf. also Kundalini, pp. 103 and 107.